1. Field of the Invention
The present invention relates to a device for moving offset plates and specifically to shift offset plates to a fixing device by grasping a plurality of offset plates equipped with positioning engagement holes as they are piled up in a stack and moving them to a fixing device through a print-through device.
2. Prior Art
Various devices are known for movement of offset plates such as aluminum base plates, zinc oxide masters, zinc plates and OPC plates, and others which have been given an anodic oxidation treatment. Offset plates are provided with a plurality of positioning engagement holes at the edge. The positioning holes are pushed onto positioning pins of a forwarding device by means of the engagement device, thereby causing the shifting device to hold the offset plate.
In the case where an object is grasped by grasping means to be moved to a prescribed location, it is ordinarily and practically impossible to move the same accurately to a prescribed location due to the manufacturing error and necessary tolerances for the parts of the grasping means. In conventional apparatus, the positioning holes are loaded on the pins in a condition in which their positions are not completely coordinated. This has the effect of producing wrinkles or destroying the positioning holes.
In addition, the offset plate after the completion of print-through does not have a natural fall from any positioning pin that has been forcefully pushed in, with a result that it is difficult for the offset plate to be dropped from the positioning pin at a prescribed time.